Various methods of manufacturing contact lenses are known, including spin casting, lathing (for example by diamond turning), and cast molding (for example, using injection molded mold halves). In particular, cast molding of contact lenses involves forming a pair of mold halves (i.e., a first mold half and a second mold half), placing a volume of a contact lens formulation on an optical quality surface of one of the two mold halves, and placing the two mold halves in contact with each other to form a contact lens mold assembly that has a contact lens shaped cavity containing the contact lens formulation. The contact lens mold assembly is then exposed to conditions to cause the contact lens formulation to polymerize or cure in the contact lens mold assembly. As understood in the art, the mold halves may be referred to as “mold sections” (i.e., first and second mold sections) or “mold members” (i.e., first and second mold members). In a typical method, after polymerization, the lens mold halves are separated (for example by prying them apart or punching one from another), in a process step referred to as “demolding”. The polymerized contact lens formulation, now in the form of an unhydrated lens, is retained in one mold half, from which the lens is removed (for example by picking it out using a vacuum pick head or by floating it off by immersing the mold half in water or another liquid); the process step of removing the lens from the mold half is referred to as “delensing”. In another method the mold halves, or at least the portions thereof that form the contact lens shaped cavity when in contact with each other, may be formed of a material that is soluble in a solvent in which the cured lens is insoluble. In such a method, the demolding and delensing may involve immersing all or part of the mold assembly in the solvent to dissolve the soluble material, thereby releasing the cured lens.
Where a lens manufacturing process employs dissolvable molds, the time to dissolve the molds can become a key to desired efficiency. Moreover, techniques to effectively delense a lens from a mold also lend themselves to desired manufacturing output.
Accordingly, there has developed a need to improve mold dissolving times in molding methods employing dissolvable molds. There has also developed a need to better separate a lens from a mold, and to best present the lens for collection.
The present disclosure addresses these and other needs.